Lock washer



E. B. CARNS 1,725,440

LOCK WASHER AugJZO, I929.

Filed April 6, 1927 Patented Aug. 20, 1929.

UNITED STATES PATENTOFFICEQ EDMUND B. cAaNsQor NEW roux, 'N. Y.

LOCK wasnm Application filed April 6, 1927. Serial No. 181,308.

.My invention relates to improvements in lock washers such as are used to prevent a screw, bolt or the like from turning.

M invention is especially useful in connection with screws having slotted heads of the conventional kind although it can be used in connection with other types of screws or bolts, as will a pear.

The invention -1s intended to produce an exceedingly cheap and simple lock washer which has means for holding it in place when a screw or the like is turned home against it and which has a plurality of outwardly extending or peripheral fingers or tongues which can be bent in to engage the slot of a'screw head or other part of a screw or bolt, and which are numerous enough so I that some of them may be certain of engaging a'screw or the like in a manner to prevent it from turning.

The invention can be used to good advantage in certain parts of air craft construction, and for such use, the washer in its simplest form is suitable. For ordinary use, I pre- 2 fer to have the washer provided with ears ing drawings, in which similar reference characters represent corresponding parts in all views.

Figure lock-washer as applied to the screw and connected parts.

Figure 2 is of Figure 1. a p

Figure 3 is a detail, partly in section and partly perspective, showing the details of the washer.

Fi re 4 is a cross section of a slightly modi ed form of the washer, and

Figure 5 is a cross section showing another modification.

' The washer has a body 10 which can convenient-ly be stamped out of thin, soft readily bendable metal and it has many peripheral fingers or tongues 11, normally lyacross section on the line 22 55 ing in the plane of the body but adapted to be folded inward, without injury, when desired. V,

' This/washer can be laced beneath the head of a screw 12 and have shown it ap plied to a screw uniting the-members 14 and 15, which, it will be understood, may be I any parts to which the screw may be applied.

through the middle through which a screw -or bolt may pass and, .in some for1ns,.it is dished toward the center, asshown in 17 so that it may fit in a counter sink 13, usually provided'for screws. y I p The washer can, also, have: at its inner edge, lugs or ears 18 which should be parallel with the axis of the washer and the screws, and these lugs maybe very small. They are somewhat exaggerated in the drawing for clearness. They can engage recesses 19 in the 'wall of the screw hole and the recesses, of course, can be small. All that is necessary is to have the washer catch 'sufiiciently to prevenitits turning. It will be noticed'gthat when the screw is The washer has anopening or hole 16 turned home, the washer will be bound very securely 'between the screw head and the part 14 so that only a little additional resistance to the turning need be rovided for.

1 is a plan view of my improved A When the screw is put throug the washer and turned home, the washer will'be held against tur ning as described and such tongues 11 as registered with the screw slot 12' can be turned or doubled over into e'ngagement with the screw head, that is, can

1 and thus the screw is locked against ad ditional turning. 'After the washer has been screwed down into position and thernarrow metal tongues" bent into the screw kerf, the structure is usually given a coating of varnish, lacquer or other protective substance. Due to the plurality of spaced metal tongues,the ex-.

ternal edge of the washer has been greatly increased. The varnish or lacquer enters between the tongues and forms a cementing medium between the washer and cover The result is that in .ordemto move the washer it is necessary for the plurality. of

tongues to sheer the varnish or lacquer.

90 f be made to enter the slot as shown in Figure sition due to the metal tongues which have been bent "into the screw slot.

For urposes such as stated, the d1sh1ng efi'ect 1g is desirable but even if the washer were flat, the pressure of the screw head would force it into the counter sink. V

In Figure 4, I have shown a modification in which the washer is perfectly flat, hasa screw hole through it and has tongues 22 mally in the plane of the washer body, but

like the tongues 11 already described.

For some purposes, this is all that is required, for 'enamplefwhere the .screw and washer are used on surfaces which are tobe varnished or covered with some siccative coatlng, the coating itself will, together'with .the screw pressure, hold the washer against turning. v

In Figure 5, I have shown the Washer 20 having lugs 23 at the inner edge to engage corresponding, recesses.

. I have described the washer as having 7 the tongues :CllS osed toengage the slot 12' of a screw'heaj but, obviously, it might be made to engage other parts of the head oi the screw or bolt, and in referring to tlie structure as a screw lock, .1 use the name screw in its broad sense.

What I claim is: y 1. An improved lock washer of soft sheet metal for use with screws, having a hole therethrough and a plurality of substantially spaced metal tongues disposed entirelyaround its outer periphery and lying normetal for use with screws, having lugs on its inner edge adapted to bend into the screw receiving hole, and substantially spaced peripher'al tongues projecting from its outer edge, lying normally in a plane of the "washer body'and adapted to be bent into a screw slot.

In testimony whereof, I have signed my name to this specification this) 4th day of April 1927.

I, EDMUND B. CABNS. 

